The present invention relates to power saws and, more particularly, to orbital-action power saws that cause a saw blade to simultaneously reciprocate along an axis of reciprocation and move in a direction transverse to the axis of reciprocation.
Various mechanical components and component organizations have been developed for portable reciprocating power saws that cause the saw blade to reciprocate along an axis of reciprocation and move in a direction transverse to the axis of reciprocation to provide a more aggressive cutting action. It is generally considered desirable that the mechanical components and their organization in the power saw provide a relatively compact power transmission that causes a minimum of dynamic unbalance and has a relatively long service life. The requirement for a relatively compact transmission is particularly important with regard to in-line reciprocating power saws which typically have a handle at the rearward end that is gripped with one hand and a forward nose portion that is gripped with the other hand. The power transmitting components are usually contained within the nose portion of the tool, and, accordingly, must be relatively compact to allow convenient gripping of the tool. Prior art mechanisms have included various types of transmission arrangements, some of which have not permitted a sufficiently compact forward nose envelope for the tool or have had limited service life because of the type of power transmission components utilized within the tool. Other prior art mechanisms have utilized nutating or wobble plate type mechanisms that provide both the reciprocating and transverse motion but often times have had a limited range of adjustment for controlling the saw orbit and are relatively expensive to fabricate. Accordingly, a need exists for a reciprocating power saw of the orbital-action type in which the transmission components are sufficiently compact to provide an easily gripped forward nose portion, have a substantial service life, and limit the vibration produced during tool operation.